1. Field of the Invention
The present invention relates to an oil filter mounting structure in an internal combustion engine.
2. Description of Background Art
A lubrication system in an internal combustion engine is generally configured in such a manner that oil accumulated in an oil pan is pumped by an oil pump, and the oil discharged from the oil pump is supplied to the respective parts to be lubricated in the internal combustion engine.
The oil discharged from the oil pump passes through an oil filter before being supplied to the respective parts to be lubricated so that impurities are eliminated from the oil.
The oil filter is mounted to a crankcase in which oil channels are configured from the outside so as to be demounted easily at the time of maintenance, and is mounted to the crankcase normally so as to protrude therefrom.
Therefore, in a vehicle-mounted internal combustion engine, the oil filter mounted to the crankcase so as to protrude therefrom is subject to disturbance during travel.
Therefore, the oil filter mounting structure disclosed in JP-A-7-317521 is such that a curved recess in the vertical direction is formed on the oil pan, which is to be connected to the lower portion of the crankcase, so as to notch part thereof, and the oil filter is mounted to the lower surface of the crankcase along the curved recess.
However, the oil filter disclosed in JP-A-7-317521 is provided on the lower surface of the crankcase along the curved recess in the vertical direction of the oil pan so as to protrude downward, and the side of the oil filter is partly surrounded by the curved recess in the vertical direction, but the lower side is opened.
Therefore, the oil filter provided in the curved recess is protected from stones coming from the front, but is not protected from stones hitting thereto from below.
Since the oil filter is arranged on the lower surface of the crankcase which is the same level as the oil pan, the lengths of a filter introducing channel of oil from the oil pump which is located at a higher level than the oil filter and a filter deriving channel from the oil filter extending to the respective parts to be lubricated located at a higher level than the oil filter increase, and hence the total amount of oil increases, whereby the crankcase which constitutes the oil channels is upsized and the weight of the internal combustion engine is increased.
In view of such problems, it is an object of the present invention to provide an oil filter mounting structure in which the oil filter is reliably protected from the stones hitting thereto and the lengths of the oil channels are reduced to achieve the compact light-weight internal combustion engine.